Fish in Roman mosaics

Fish (and other aquatic creatures) in Roman mosaics

A very common theme these mosaics have given us some good information on the types of fish caught at that time.

When you look at the colours used in the polychrome ones notice how the shades graduate, is it dark on top going to light, dark at the top and bottom and light in a bad along the centre showing the rounded shape? There are many variations.

Notice also how they show different features such as the gills, the mouth etc.